In the art of autofocus cameras, a passive system has been developed where light from a remote object passes through the taking lens of the camera and then passes through a plurality of lenslets so as to create images of the exit pupil of the taking lens on pairs of detectors mounted behind the lenslets, the detectors usually being part of an integrated circuit chip. Such a system is found in the Norman L. Stauffer U.S. Pat. No. 4,185,191, issued Jan. 22, 1980.
In a co-pending application, Ser. No. 249,032, filed Mar. 30, 1981 now U.S. Pat. No. 4,425,501 in the name of Norman L. Stauffer, and assigned to the present assignee, an opto-electronic package is shown wherein a plurality of detector pairs and circuit components occupy a circuit chip over which a plurality of lenslets are placed and then on top of the lenslet array, a masking structure is placed so that light passes only through the lenslets and not through the areas adjacent the lenslets on the lenslet array. A corrector lens and a filter are also shown in this prior application and, although not shown, the die containing the detector pairs and electronic circuitry is normally attached to a substrate and a transparent cover is placed over the components and fixed to the substrate so that the unit may be sold to camera manufacturers for use in their autofocus circuits. The package above-described involves considerable manual effort to assemble which causes an undesirably high cost and furthermore, the lenslet array being made of plastic, can produce errors since it has a higher co-efficient of thermal expansion than do the silica and alumina components with which it is associated. Efforts to reduce the cost have been accomplished in, for example, elimination of the corrector lens and the bonding of a dichroic filter to the cover in order to reduce the number of components being assembled. Unfortunately, the remaining components are still too many to reduce the cost significiantly and the problem of the plastic having a higher temperature co-efficient still remains.